Pin ovens are well known in the art and are widely used in the food and beverage can manufacturing industry for drying the coatings on the exterior of partially completed, open-ended, steel and aluminum cans. The coating applied to the exterior of the cans may include an ink or enamel used to apply the label, an overcoat of lacquer or varnish, or both, a printed label and overcoat.
A typical pin oven includes a conveyor chain mounted for movement in a generally vertical serpentine path defined by a series of straight runs connected by curved sections. Carrier pins are attached to the conveyor chain in spaced relation along its entire length substantially perpendicular to the chain conveyor. The open-ended cans are placed onto the extended pins and are carried over the serpentine path through the oven. Nozzles aligned with the chain path and the cans direct heated air against the outside of the cans as they travel through the oven.
The heated air streams are also intended to stabilize the cans on the chain pins and, therefore, most pin ovens include nozzle arrangements which continuously direct heated air against the can bottoms. Also to facilitate maintaining the cans on the chain pins, pin ovens typically are tipped off vertical center a few degrees. Other prior art patents eliminate can flopping or flutter over the path of movement through the oven by various means.
It is also known to dry inks and finishes applied to the exterior of cans in pin ovens in which the pins include holding apparatus which contact the cylindrical interior of the cans and hold them centered on the pins as the pin chain travels through the oven.
Can manufacturing plants utilize pin ovens typically operating around the clock, seven days per week. Accordingly, energy consumption, both in terms of natural gas used to fuel the air heaters and electricity to operate the blower motors and conveyor motors is very substantial. Thus the ability to process cans in greater volumes with lower time spent in the oven and without increasing air temperature above the desirable maximum, can provide a substantial savings and energy costs. In addition, reducing the amount of natural gas used in the air heaters also substantially lowers the cost of operation as well as reduces gas emissions.
The apparatus of the present disclosure must also be of construction which is both durable and long lasting, and it should also require little or no maintenance to be provided by the user throughout its operating lifetime. In order to enhance the market appeal of the apparatus of the present disclosure, it should also be of inexpensive construction to thereby afford it the broadest possible market. Finally, it is also an objective that all of the aforesaid advantages and objectives be achieved without incurring any substantial relative disadvantage.